| 摘要 |
<p>Hard metal carbide bodies are produced by re-crystallizing a mixture of hard metal carbides consisting predominantly of titanium carbide by heating, comminuting the re-crystallized carbides and intimately mixing with nickel powder and with one or more other powdered binder metals, heating the mixture, the proportion of binder metals to carbides and the temperature being sufficient to melt the binder metals and form a binder-carbide eutectic, comminuting the mixture and pressing and sintering to form the body. The hard metal carbide is preferably predominately titanium carbide and may also contain niobium carbide, tantalum carbide, iron carbide, and tungsten carbide and the binder metal is preferably nickel with or without chromium, cobalt, manganese and ferrotitanium. In one example, a ball-milled mixture of titanium carbide and tantalum-columbium carbide was passed at a rate of 1/2 inch per minute through a furnace at 2600 DEG C. and the re-crystallized carbide, were crushed to -100 mesh. A powdered binder mixture of 50 per cent chromium, 50 per cent nickel was then prepared and sintered at 1050 DEG C. and the binder was mixed with the carbide in the proportion of 85 per cent carbide, 15 per cent binder. The binder-carbide mixture was pre-sintered at 1250 DEG to 1200 DEG C., granulated and passed at 1/2 inch per minute through a homogenizing furnace at 1900 DEG C. to form the binder-carbine eutectic. The mass was then cooled, crushed and ball-milled to 5 micron size and the bodies formed by pressing and sintering. In another example, a powdered binder mixture of 35 per cent manganese, 42.5 per cent chromium and 22.5 per cent nickel was sintered at 950 DEG C. and mixed, with the carbide in the proportion of 70 per cent carbide, 30 per cent binder. The mixture was pre-sintered at 1050 to 1150 DEG C. and homogenized at 1,750 DEG C. In a further example, a powdered binder mixture of 37.5 per cent chromium, 37.5 per cent nickel and 25 per cent ferrotitanium was sintered at 100 DEG C. and mixed with the carbides in proportion of 70 per cent carbide, 30 per cent binder. The mixture was pre-sintered at 1150 to 1200 DEG C. and homogenized at 1750 DEG C. The Provisional Specification includes the use of a single carbide and a single binder metal, whilst in Example 1 the mixed carbides contain 3-4 per cent iron carbide and homogenization takes place at 1850 DEG C.</p> |
